Mixing and shaking devices are widely used in a variety of laboratory applications, and may, for instance, be used in the food safety and water safety industries to test various samples. At times, such samples may initially include undissolved solids that will need to be broken up during the mixing operation. For instance, many test requirements for determining the presence of harmful chemicals, pesticides, bacteria, etc., require that larger volumes of liquid be shaken together with amounts of soil and/or vegetable matter. When shaking a mixture containing solids, it may also be desirable to break up the solids by employing a metal or ceramic ball or cylinder inside the sample tube being used to assist in macerating the solids in order to improve any chemical reaction.
While compact shakers have been available in the past for processing biological specimens in microplates, there exists a need for a shaker capable of effectively mixing larger volumes, for example up to 50 ml fluid samples, as may be required in food safety and water safety tests and that will sufficiently mix samples even when solids are present in the samples.
Linear, or essentially linear, shaking is desirable in the above instance because the relatively heavy ball or cylinder introduced to aid in breaking up the mixture works best when shaken rapidly in this essentially straight line motion. The heavy mixing ball or cylinder (if employed) can be driven from one end of the liquid containing specimen tube to the other completely breaking up the contained solids uniformly.
Larger specimens require a shaker that is well-balanced and that particularly properly balances forces on the apparatus during a mixing operation so as to minimize vibration and noise of the overall apparatus. It is desirable, therefore, to achieve a balance that can simultaneously maximize mixing while minimizing vibration and noise of the apparatus as a whole, without increasing the mass of the apparatus beyond a reasonable size suitable for laboratory use.
Moreover, various specimens have varied mixing requirements. Little prior success has been achieved in providing easily adjustable mixing apparatus for large volumes of liquid.